Existing commercial photographic silver halide colour materials form dye images by the reaction of oxidised p-phenylenediamine colour developers with a colour coupler. The colour developing solutions employed contain the colour developing agent and used developer solutions need to be disposed of safely. Attempts have been made to incorporate p-phenylenediamine colour developing agents into silver halide photographic materials but these have had little success largely due to the pronounced staining produced.
The use of sulphonhydrazides as colour developers in aqueous colour developer solutions which form an azo dye on coupling with a colour coupler are described in U.S. Pat. Nos. 2,424,256, 4,481,268 and copending British Application No. 9125688.3.
A problem encountered with this system is that it is difficult to obtain the desired hue for the cyan image.